Determination of bending-induced strain in optical fibers by use of quantitative phase imaging

Quantitative phase microscopy with polarized light has been used to determine the change in refractive index introduced into an optical fiber when the fiber is bent through a constant radius of curvature. By obtaining phase images for two orthogonal directions of the polarization of the incident light, one can infer the induced axial strain profile within the fiber. Radii of curvature from 1 to 8 cm were considered, and in each case excellent agreement, within lambda/100, was obtained between experimental results and theory.     

Relation between orbital binding energies and ionicities in alkali and alkaline earth flourides

The differences between the ionization potentials and binding energies for M^q+ (np⁶), F^?(1 s²), andF^?(2p⁶) orbital electrons, adjusted for the electrostatic self-potentials, in alkali and alkaline earth fluorides have been correlated with ionicites derived from the indices of refraction through optical dispersion theory of Phillips and van Vechten. The differences are linear in ionicities and are related to the covalent energies and the polarizabilities. The gap between the valence band and the Fermi level, determined with X-ray photoelectron spectroscopy, has been compared with the energy in the Phillips-van Vechten model. Whereas the former is a measure of the thermal activation energy for conduction, the latter is determined essentially by the valence electron density, the molar volume, and the polarizability.     

Relation among x-ray photoelectron intensities,cross sections and kinetic energies in insulating solids

The fundamental relation among X-ray (MgK_α) photoelectron intensities, theoretical orbital ionization cross sections, and photoelectron kinetic energies has been investigated through precisely measured relative intensities of orbital electrons from sublimed-condensed samples of KF, NaF, CaF₂ and KG, and other ionic solids. Although the results confirm within approximately 15% the relation and establish a linear dependence of the intensities on analyzer transmission, they suggest that either a slight deviation from the relation exists or a cancellation of errors occurs. Empirically it is found that the relative intensities are proportional to the square of the ratio of kinetic energies, and with this relation, the intensities agree with the theoretical cross sections within a few per cent. This relation suggests that the dependence on the angular parameter is inconsequential and that the mean free path is proportional to the kinetic energy.     

Measurement of the two-loop lamb shift in lithiumlike U89+

Using the SuperEBIT electron beam ion trap, we have measured the 2s(1/2)-2p(1/2) transitions in U88+ and U89+. The measured value of 280.645 +/- 0.015 eV for Li-like U89+ improves the available precision by nearly an order of magnitude and establishes a new benchmark for testing the total QED contribution to the transition energy within a fractional accuracy of 3.6 x 10(-4). We infer a value for the 2s two-loop Lamb shift in U89+ of -0.23 eV, from which we estimate a value of -1.27 eV for the 1s two-loop Lamb shift in U91+.     

An exact operator solution of the quantum Liouville field theory

Exact, closed form results are given expressing the quantum Liouville field theory in terms of a canonical free pseudoscalar field. The classical conformal transformation properties and a Bäcklund transformation of the Liouville model are briefly reviewed and then developed into explicit operator statements for the quantum theory. This development leads to exact expressions for the basic operator functions of the Liouville field: ?_μΦ, and e^nΦ. An operator product analysis is then used to construct the Liouville energy-momentum tensor operator, which is shown to be equal to that of a free pseudoscalar field. Dynamical consequences of this equivalence are discussed, including the relation between the Liouville and free field energy eigenstates. Liouville correlation functions are partially analyzed, and remaining open questions are discussed.     

Computing the KAC determinant using dual model techniques and more about the no-ghost theorem

We relate some mathematical results concerning the Virasoro algebra to properties of dual models. Specifically, we show how to compute the Kac determinant using well known techniques from dual models. Then we use the Kac formula to discuss the validity of the no-ghost theorem of dual models in a more general setting than the original proofs of that theorem.     

Kinetics of the reaction of O(3P) with CF3NO

A laser flash photolysis-resonance fluorescence technique has been employed to study the kinetics of the reaction of O(³P) with CF₃NO (k₂) as a function of temperature. Our results are described by the Arrhenius expression k₂(T) = (4.54 ± 0.70) × 10^?12 exp[(?560± 46)/T] cm³molecule^?1 s^?1 (243 K ? T ? 424 K); errors are 2σ and represent precision only. The O(³P) + CF₃NO reaction is sufficiently rapid that CF₃NO cannot be employed as a selective quencher for O₂(a¹Δ_g) in laboratory systems where O(³P) and O₂(a¹Δ_g) coexist, and where O(³P) kinetics are being investigated. © 1995 John Wiley & Sons, Inc.